An air-drop mission can apply to:                personnel (parachutists);        materiel, for example food, tents, vehicles, or weapons.        
The air-drop zone, also called the “Drop Zone”, is a rectangular zone in which the materiel or the personnel must fall. It is defined by an entry point, an exit point, a width and an altitude.
To accomplish the air-drop in a planned zone, the aircraft follows a standardized flight pattern, called the air-drop pattern.
The air-drop pattern is the known flight trajectory labeled by points named AP, CARP, EOD, EORP and the REDO trajectory which are defined hereinafter:                AP: “Alignment Point”—lateral alignment of the aircraft, this point allowing people in cargo bays to prepare the materiel to be air-dropped by leveling off the aircraft between this point and the following point CARP;        CARP: “Calculated Air Release Point”—air-drop, the start of air-drop starting at this point, also called the “green light”;        EOD: “End Of Drop Pattern”—end of air-drop, the end of air-drop taking place at this point also called the “red light”;        EORP: “End Of Run Point”, the aircraft remaining level between the points EOD and EORP so that people in the cargo bay have time to close the cargo bay and secure any remaining materiel;        REDO: being the trajectory that the aircraft must follow in order to return to the point CARP if it did not have time to air-drop everything when it arrived at the point EOD.        
FIG. 1 illustrates these points and this trajectory 10 by a view from above, aligned with the air-drop zone 1. These points are determined taking the environmental and mechanical constraints into account. These constraints are in particular the speed and the direction of the aircraft, the speed and the orientation of the wind, the altitude, the type of parachutes, the mass to be air-dropped, the type of air-drop, in particular depending on whether it involves personnel or materiel. The wind considered is a mean wind which takes account of the real gradient, the characteristics of the wind 2 being provided for a weather system.
It is the flight mission system (FMS) which determines the points AP, CARP, EOD, EORP and the REDO trajectory as a function of the parameters of the air-drop zone and of the above constraints, the parameters of the zone being in particular the entry point, the exit point, the width and the altitude of the air-drop. These parameters as well as the environmental and mechanical constraints are determined manually by the pilot and input manually by the pilot into the FMS.
A predefinition of the flight trajectory is performed in the main before the mission and then an adjustment is often made in flight, either according to the flight conditions, or on recognition of the zone, or identification or search on the ground. An automatic input and computation means is in this context necessary in order to reduce the operator's burden. Indeed, the existing solutions exhibit the following drawbacks:
In recent avionics suites possessing the air-drop function, the air-drop patterns form an integral part of the FMS, all the parameters being input manually by the pilot;
A lack of real-time graphical representativity, the operator inputting the technical values and thereafter obtaining a graphical representation of his pattern, that he can then correlate with his flight plan, or a charting background, confirming that the parameters are correct. In case of error, the operator must re-open the man-machine interface panel, modify the parameters and validate the pattern again on the flight plan or the chart, this process possibly being repeated several times, thus increasing the pilot's cognitive burden;
A loss of time for the pilot who should concentrate on flight management rather than on the correct fulfillment of his mission;
Moreover, this type of pattern is present only on certain recent flight computers, not being available in older avionics suites. It is therefore sought to afford a solution allowing the “retrofitting” of the former avionics suites by the addition of new functionalities independent of the avionics system and based in particular on onboard touchscreen tablets.
To summarize, the following are current problems:
The number of parameters involved in the computation of the pattern is significant;
In the case of an FMS, the parameters are currently input manually by the pilot. Should the pattern be modified, in terms of orientation or position, or should there be a change of environmental parameter, for example the weather, the pilot must rapidly modify his flight pattern, the manual inputting of the parameters increasing the pilot's cognitive burden;
If this function is not available in an FMS, the pilot must evaluate these parameters manually on paper.